The investigators will study the efficacy of long pulsed laser treatment for psoriasis. Psoriasis is a common disease which is often chronic in nature. Current treatment modalities do not result in a cure of this chronic disease. The investigators wish to develop a safe and efficacious dye laser for psoriasis. The laser radiation will be optimized for its selective absorption by erythrocytes in the capillaries of the dermal papillae. Subsequent thermal necrosis of the microvasculature and surrounding skin structures is expected to reduce the interaction of the papillary dermis with the epidermis and temporarily halt the disease process. Preliminary results show that 0.4 msec pulses from a dye laser can reduce the thickness of a psoriatic plaque. This phase I effort will construct a 1.5 msec dye laser to expand the zone of damage and improve responsiveness of the psoriasis. PROPOSED COMMERCIAL APPLICATION: The commercial potential of the laser is quite good if it is successful at treating psoriasis and maintaining a remission for a period of months. Currently, topical corticosteroid therapy is quite expensive as pointed out by the authors. In addition, retinoids, antimetabolites and light therapy are all expendsive with significantly more toxicity than would be experienced with most laser therapy.